1. Field of the Invention
The present invention relates to an optical amplification module including an optical waveguide having an optical waveguide region doped with a rare earth element, an optical amplifier or a white light source including the optical amplification module and means for supplying pumping light into the module, and an optical communication system including the optical amplifier.
2. Related Background Art
An optical communication system lets signal light propagate in an optical fiber transmission line to implement large-capacity high-speed transmission of information. As wavelength bands of the signal light in this optical communication system, the C-band (1530 nm to 1565 nm) is now under use, and use of the L-band (1565 nm to 1625 nm) is also under study. For the pursuit of greater capacity, use of the S-band (1460 nm to 1530 nm) is also under study as a wavelength band of the signal light.
In the optical communication system, an optical amplifier is used in order to amplify the signal light. An optical amplifier capable of amplifying the C-band or L-band signal light is an EDFA (Erbium-Doped Fiber Amplifier) using as an optical amplification medium an optical amplification fiber having an optical waveguide region doped with Er (erbium) (EDF: Erbium-Doped Fiber). When pumping light (in the 0.98 μm wavelength band or 1.48 μm wavelength band) is supplied into the EDF, the EDFA can amplify the C-band or L-band signal light propagating in the EDF.
On the other hand, a TDFA (Thulium-Doped Fiber Amplifier) using as an optical amplification medium an optical amplification fiber having an optical waveguide region doped with Tm (thulium) (TDF: Thulium-Doped Fiber), is under study as an optical amplifier capable of amplifying the S-band signal light. When the pumping light (in the 1.05 μm wavelength band, 1.2 μm wavelength band, 1.4 μm wavelength band, or 1.55-to-1.65 μm wavelength band) is supplied into the TDF, the TDFA can amplify the S-band signal light propagating in this TDF.